The FBI said it has reopened investigations into Hillary Clinton's use of private email server when she was secretary of state due to likelihood of new information coming to light, immediately drawing praise from the White House frontrunner's Republican rival Donald Trump.

With just 11 days to go before the Nov. 8 election, FBI Director James Comey said in a letter to several congressional Republicans that the agency had learned of the existence of emails that appeared to be pertinent to its investigation. (AP)

The FBI today said it has reopened investigations into Hillary Clinton’s use of private email server when she was secretary of state due to likelihood of new information coming to light, immediately drawing praise from the White House frontrunner’s Republican rival Donald Trump.

FBI Director James Comey, in a communication to the Congressional leadership, said the FBI has learned of new “emails that appear to be pertinent” to their investigation.

“In connection with an unrelated case, the FBI has learned of the existence of emails that appear to be pertinent to this investigation,” Comey wrote in the letter.

“I am writing to inform you that the investigative team briefed me on this yesterday, and I agreed that the FBI should take appropriate investigative steps designed to allow investigators to review these emails to determine whether they contain classified information, as well as to assess their importance to our investigation,” Comey said.

The FBI’s decision to reopen the investigation was welcomed by Republican presidential nominee Donald Trump as a “big day” soon after the announcement.

The controversial billionaire from New York departed from his prepared speech as he landed for his rally in Manchester in New Hampshire. “I have a breaking news for you,” he told his cheering supporters, who waited for him for hours today.

“FBI has just sent a letter to the Congress that they have found new emails pertaining to the former Secretary of State Hillary Clinton’s email investigation. And they are reopening the case into her illegal and criminal conduct that threatened the national security of the United States,” he said.

“I have great respect for the fact that the FBI and the Department of Justice are now willing to have the courage to right the horrible mistake that they made,” Trump said and hoped that “perhaps finally justice would be done.”

“This is a big day,” he said alleging that the email scandal is bigger than Watergate. ” Hillary Clinton’s corruption is on a scale that we have never seen before.”

Other Republican leaders also welcomed the decision.

House Judiciary Committee Chairman Bob Goodlatte said the move shows Clinton and her team “committed wrongdoing and jeopardised national security.”

House of Representative Speaker Paul Ryan said Clinton has nobody but herself to blame. “She was entrusted with some of our nation’s most important secrets, and she betrayed that trust by carelessly mishandling highly classified information,” he said.

“This decision, long overdue, is the result of her reckless use of a private email server, and her refusal to be forthcoming with federal investigators. I renew my call for the Director of National Intelligence to suspend all classified briefings for Secretary Clinton until this matter is fully resolved,” Ryan said.

Trump’s campaign manager Kellyanne Conway called this a great news. “A great day in our campaign just got even better. FBI reviewing new emails in Clinton probe,” she tweeted.

Other Republican leaders also welcomed the decision.

House Judiciary Committee Chairman Bob Goodlatte said the move shows Clinton and her team “committed wrongdoing and jeopardised national security.”

House of Representative Speaker Paul Ryan said Clinton has nobody but herself to blame. “She was entrusted with some of our nation’s most important secrets, and she betrayed that trust by carelessly mishandling highly classified information,” he said.

“This decision, long overdue, is the result of her reckless use of a private email server, and her refusal to be forthcoming with federal investigators. I renew my call for the Director of National Intelligence to suspend all classified briefings for Secretary Clinton until this matter is fully resolved,” Ryan said.

Trump’s campaign manager Kellyanne Conway called this a great news. “A great day in our campaign just got even better. FBI reviewing new emails in Clinton probe,” she tweeted.